1. Field of the Invention
The present invention relates to a novel amide compound having a glutamate receptor inhibiting activity and salts thereof.
2. Description of the Prior Art
The presence of chemical substances in spiders which paralyze the nerve of anthropodes such as insects has been elucidated and such substances have been isolated. It has also been confirmed that the nerve paralyzing action of those substances is due to glutamic receptor inhibiting action [N. Kawai, A. Miwa, T. Abe, Brain Res., 247 169-171 (1982); N. Kawai, A. Miwa, M. Saito, M. Yoshioka, Microelectrophoretic Investigations of Mammalian Central Transmitters, Aug. 25, 1983, Camberra, Australia, Lecture Summaries p. 4; N. Kawai, A. Miwa, M. Saito, M. Yoshioka, 29th Congress of the International Union of Physiological Sciences, Aug. 29, 1983, Sydney, Australia, Lecture Summaries p. 89; N. Kawai, 8th Conference en Neurobiologie, Nov. 25, 1983, Gif, France, Lecture Summaries, p. 10; N. Kawai, A. Miwa, T. Abe, Advances in Biological Psycopharmacology, 37 221-227 (1983); T. Abe, N. Kawai, A. Miwa, J. Physiol., 339 243-252 (1983); N. Kawai, A. Miwa, T. Abe, Biomed. Res. 3 353-5 (1982); N. Kawai, S. Yamagishi, M. Saito, K. Furuya, Brain Res. 278 346-349 (1983); and Japanese Patent Kokai No. 60-184021 published on June 19, 1985]. Some of chemical structures are reported. For instance, "Proceedings of the Japan Academy", 62 Ser. B, 359 (1986) discloses N.sup.1 -(2,4-dihydroxyphenylacetylasparaginyl)-N.sup.5 -(arginylcadaverino-.beta.-alanyl) cadaverine and the like and Chemical PG,3 Abstracts, 105: 186106d (1986) discloses (2,4-dihydroxyphenylacetylasparaginyl)-polyamine-(arginyl) wherein the polyamine is --NH(CH.sub.2).sub.3 NH(CH.sub.2).sub.3 NH(CH.sub.2).sub.5 NH--.
Problems come up what is the essence of the action of the glutamate receptor substances including the above chemical substances and what chemical modification is possible.
The inventors synthesized compounds having a part of the structure of the above chemical substances and the above chemical substances which were chemically modified and studied their glutamate receptor inhibiting action to find that the glutamate receptor inhibiting action is developed by bonding a certain group to the partial structure of the above chemical substances. As a result of further investigation, the present invention has been accomplished.